The present invention relates to a split outer race, to a split rolling bearing using the split outer race, and to a manufacturing method for a split outer race. This split rolling bearing is used in a structure using a shaft as an inner race member, for example, in a connection portion between a crankshaft of an automobile engine and a large end part of a connecting rod thereof.
For instance, a rolling bearing used in the connection portion between the crankshaft and the large end part of the connecting rod has paired split outer races, plural rollers circumscribed on the inner surfaces of the paired split outer races, and paired split cages for holding the rollers arranged in such a way as to be substantially equally spaced in a circumferential direction thereof. The split outer races are produced by using, for example, bearing steel to thereby manufacture a cylindrical outer race, and by thereafter splitting the cylindrical outer race into two. To split the cylindrical outer race into two, notches for inducing splitting are provided in a part of the cylindrical outer race. Then, the cylindrical outer face is split by applying an external force thereto by pressing (see, for instance, JP-A-7-317778).
However, at the splitting, most of cracks produced in the notches extend therefrom straightly along an axial direction. Thus, when a split rolling bearing using the split outer races is incorporated into the place of use, the paired split outer races are apt to be displaced in an axial direction. Additionally, a processing stress generated at the splitting causes both ends of each of the paired split outer races to open in the direction of an outside diameter. However, the degree of opening of each of the split outer races is not constant. When the paired split outer races are combined with each other, both ends of each of the split outer races are displaced in a radial direction, so that a step-like part due to a difference in inside diameter between the outer races is apt to be produced at an abutting portion at which both ends of one of the split outer races abut against the corresponding ends of the other split outer race. Thus, when the rolling bearing is in a used condition, the rollers, which roll on the inner surfaces of the paired split outer races, ride on the step-like portion, so that vibrations and noises are generated.